<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">

    <!-- meta标签 -->
    <!-- html4.0 - 自动跳转 - 过5秒自动跳转到url后面的链接 -->
    <!-- <meta http-equiv="refresh" content="5;url=http://www.baidu.com"> -->

    <!--自动刷新本页面-->
    <!-- <meta http-equiv="refresh" content="1"> -->

    <meta name="auther" content="doumenghan">
    <meta name="keywords" content="html基础学习">
    <meta name="description" content="学习标签和html结构">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">


    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>标签</title>
</head>
<body>
    <!-- 字体标签 -->
    <font color="red">字体标签font</font>
    <font color="#ADFF2F">十六进制颜色值</font>
    <font color="rgb">rgb</font>
    <!-- 单标签 - 水平线  -  快标签 -->
    <hr>
    <br>
    <br>
    <!-- 字体的size级别只有1~7，数字越大，字体越大 -->
    <font color="green" size="5">字体颜色大小</font>
    <br><br><br><br>

    <!-- 标题标签 -->
    <h1 align="center">
        <font color="red">一级标题</font>
    </h1>
    <h2 align="center">二级标题</h2>
    <h3 align="center">三级标题</h3>
    <h4 align="center">四级标题</h4>
    <h5 align="center">五级标题</h5>
    <h6 align="center">六级标题</h6>
    <br><br><br><br>

    <!-- 文本标记 -->
    <b>粗体</b>
    <strong>strong</strong>
    <i>斜体</i>
    <em>u斜体</em>
     <!-- 指定上标 -->
     X<sup>2</sup>

     <br><br>
 
     <!--实体-->
 
     <!-- 空格 &nbsp; -->
     实&nbsp;&nbsp;&nbsp;&nbsp;体
 
     <!-- 大于,小于,大于等于,小于等于 -->
     3&gt;2 2&lt;3   3&ge;3  5&le;5  6!=7
 
     <br>
 
     <!-- 指定版权 -->
     &copy;
 
     <!--商标-->
     &reg;

    <u>O<sub>2</sub></u>



</body>
</html>